The first - and only - history of the Secret Intelligence Service, written with full and unrestricted access to the closed archives of the Service for the period 1909-1949.

'Reads like the script for a Bond film' Mail on Sunday A groundbreaking book, this unprecedented study is the authoritative account of the best-known intelligence organisation in the world. Essential reading for anyone interested in the history of espionage, the two world wars, modern British government and the conduct of international relations in the first half of the twentieth century, MI6: The History of the Secret Intelligence Service 1909-1949 is a uniquely important examination of the role and significance of intelligence in the modern world.

"‘Extraordinarily useful, endlessly interesting ... Jeffery captured the adventurous, John Buchan side of SIS with as much zest as he revealed the successes and failures of its analysis of events'" - John Simpson

"'A magisterial account of the two wars in particular, viewed via the prism of secret intelligence. Winningly, it also entertains'" - Independent on Sunday

"‘Fascinating ... The book is full of examples of the ingenuity and courage shown by all ranks'" - Douglas Hurd, Guardian

"'Full of episode and personality, without ever succumbing to the swash and buckle that can dazzle those who get close to SIS'" - Daily Telegraph